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Posted: Thu Nov 03, 2011 4:37 pm
by bigtone
Hi to you all,
My first post so here goes.
I am a carpenter and have purchased a barn in the south of france to convert. The ground floor is earth and needs to be dug out to lay a concrete slab. I have never done one before so was after some information as to how its done. I've read up on the basics i.e. hardcore, sand, dpm, insulation etc but just need a point in the right direction. Also, the ground floor area is over 150m2 and this cannot obviously be done in one go so how is it done in sections? I'm also assuming that to take any weight of upright beams supporting the first floor, I have to dig out deeper where the uprights will be.
Also, whats the thickest screed recommended, i.e is it usual to lay copper pipes in the screed? I wont need to lay anything large like waste pipes just electric cable and copper +6pipe.
Any help on this would be greatly appreciated,
Big Tone
Posted: Thu Nov 03, 2011 6:20 pm
by lutonlagerlout
well big T as you and my dad and me share the same nickname,welcome to the brew cabin :;):
a lot depends on what the structure is sitting on
you need a structural engineer and i am guessing it will need to be signed off by the local building control
over here 150 type1 blinded with sand and wacked,1200 gauge dpm,100mm celotex or similar,100mm of concrete (slab mix)
then 70mm of floor screed (more if you are having underfloor heating)
so thats 420mm of dig below finished floor height
17inches in old money
but and I cannot stress this enough,you need a SE to assess the structure and also local building control
get it wrong and the barn falls down
any more questions ask away
cheers LLL 
Posted: Thu Nov 03, 2011 9:22 pm
by bigtone
Thanks for that LLL. Thats a good start on quantities. What about doing 150m2 in sections? How do you section off a bit at a time without piercing the dpm? I'm assuming with 150m2 its easier to do it by the lorry load of concrete?
I do have an SE who does the drawings for my loft conversions and he's offered to fly over with me to have a look. Its a very sound stone barn with 600mm thick walls (gonna be fun knocking out for window and door openings!)
Posted: Thu Nov 03, 2011 9:34 pm
by bigtone
Its also very strange in France. You do your building work and sign it off yourself. They're of the thinking that if you build a house and it falls down on you then thats your fault! There are also very strict regulations for building companies. The only ones who can do bad jobs are the ones that are not registered. That again is your fault as you are not supposed to use them and they are not supposed to work.
Posted: Thu Nov 03, 2011 9:40 pm
by lutonlagerlout
its not that much about 15m3
probably do it in 3 pours,you would have a shutter 400 back from the edge of the dpm with rebar through it
your engineer mate will tell you the nitty gritty
you need to find a french concrete company now
cheers LLL
Posted: Sat Nov 05, 2011 10:55 am
by seanandruby
why can't you do it in one pour , less work, no shuttering, start at the back, pumping it and t tamp on the way out ???
Posted: Thu Nov 10, 2011 10:34 am
by GB_Groundworks
me and my guy are pouring/pumping 40m3 tomorrow on our tod, for NHS at wrexham. hopefully the steel crew have got the shutters level this time lol, 15m3 is half a mornings work then a cuppa and finish. as its internal you'll need expansion material around the permiter and maybe a few crack control joints but engineer will spec that.
if its an old barn chances are it hasnt go any footings so you are going to have to dig down in 1m wide sections and under pin it as you digout, throw a rebar cage in, shutter pour working in 1m section caste-let sytle _[-][-] etc
then dig out stone etc mot, use plastic pipe not copped lot easier/cheaper for underfloor heating
Edited By GB_Groundworks on 1320921332